What is the visual cue that indicates an interactive shell is waiting for the user to type a command?

The visual cue that signifies an interactive shell is ready for user input is known as the prompt. This prompt typically displays a special character or set of characters, such as a dollar sign ($) for standard users or a hash mark (#) for the root user in many Unix-like systems. The prompt indicates that the shell has finished processing the previous command and is awaiting a new command from the user.

The prompt is an essential aspect of the command-line interface, as it provides users with an indication of where they can start typing their commands. This visual representation helps differentiate between the shell's output and the user's input area, facilitating a smooth interaction and efficient command execution.

In this context, other terms used in the options relate to different concepts within command-line usage. "Command" refers to the instruction entered by the user for the shell to execute, while "Option" typically refers to additional parameters that modify the behavior of a command. An "Argument," on the other hand, is specific data that is passed to a command, which helps define its operation. These terms do not serve as indicators of the shell's readiness for input, which is why they are not the correct answer in this scenario.